Ventilation systems are commonly used to provide fresh air to interior spaces of buildings in order to provide climate conditioning and control. Such systems often are used to deliver a quantity of fresh or “make-up” air to the building interior so that stale, polluted, or otherwise undesirable air within the building ca be at least partially replaced with fresh air. To that end, ventilation systems are oftentimes located exterior to the building itself, such as on the rooftop or adjacent to an outer wall, so that ready access is provided to fresh air and so that the replaced air can be easily dispersed to the atmosphere.
However, such exterior placement of the ventilation system also results in the system being exposed to the elements, including to precipitation that might occur. This exposure is especially pronounced when the ventilation system is situated on the rooftop of a building, where it might not be easily sheltered from the elements.
In general, the undesirable ingress of precipitation (for example, rainwater) into the ventilation system itself can be avoided through the proper design of the ventilation system enclosure. However, the substantial quantity of fresh air that can be induced to flow into the ventilation system in order to provide its desired functionality can cause a significant amount of precipitation to be ingested in along with the fresh air. This precipitation, usually but not always rainwater, is entrained in the air flow due to the relatively strong suction effect of the ventilation system. The ingested rain water can collect within the system, or can be discharged into the interior space of the building, neither of which is desirable.